Bar codes are now widely used for ready identification of products at goods-in and check-out locations associated, for example, with retail trading. They facilitate the use of fully automatic in-and-out systems and, in some instances, do away with the need for price labels on the products. Many supermarkets stock 25,000 to 30,000 items for sale, however, and do not have sufficient shelf space to allocate all of these items to a particular position; as a result, even if there is a bar code on such products, there is still a need for price marking. Nevertheless, the use of bar code scanning system to identify the goods may reduce labour requirements significantly and thus produce considerable savings.
In supermarkets, typically 95-96% of food items going through the check-out have a bar code already printed at source by the manufacturer. For non-food items, the number of products bar coded at source is typically 80-85% of those going through the check-out.
In order to apply price labels to items already carrying a bar code, and to add a bar code to those products which are not coded at source, it is common for a retail outlet to use one or more label printers. These may be hand-held or fixed in position. Typically, three stationary printers may be used by up to ten people. Strips of labels will be printed and taken to the product and either applied by hand or with a dispenser. Some retailers consider that it is more economical for each operative to have his own hand-held bar code label printer.
If a national bar code has been allocated to a given product, this will normally be used by the retailer if no manufacturer's bar code is present. For products where no such national bar code has been allocated, it is up to the retailer to decide on his own bar code number. Typically, this number might be based on the numbering system used by the retailer before the introduction of bar code scanning to his store. In practice, the person generating bar codes with a printer will have with him source material which indicates the nature of the bar code for each product where a label is required.
Hand-held labelling machines typically comprise a housing which is arranged to store a label supply roll; a printing unit; and a keyboard for inputting data. When such a machine is used to print bar code labels, an operative will input the bar code number via the keyboard, which then activates a label feed mechanism and the printing unit to apply the requested bar code to one of the labels on the supply roll. After the bar code has been printed, the label feed mechanism moves the supply roll so that the printing label is accessible for application to the appropriate goods item.
Packaging materials vary widely in the nature of the material from which they are fabricated, in background colour and in finish. Current bar codes are in the form of black indicia on a white background. These factors encourage the use of labels which provide a background which is uniform in quality and colour.
While the use of labels as a vehicle to carry bar codes is, in many instances, convenient and effective, nevertheless there are certain situations in which this standard technique causes problems. For example, many items are packaged in small units with substantially all of their exterior surface carrying graphic displays and consumer information. In such cases, the application of a label may obscure data which is intended to be displayed. Printing a bar code onto a label necessitates transfer of the label to the goods; when dealing with a large volume of products, the label transfer step makes a significant contribution to the overall time involved in the labelling exercise and consequently contributes to the overall cost involved in generating and applying bar code labels.